1. Field of the Invention
The present invention relates to a communication method and system that adapts to channel and/or propagation conditions, and more specifically, an intelligent radio module (IRM) that optimizes performance of channel units in a gateway.
2. Background of the Related Art
FIGS. 1 and 2 illustrate a related art processing system. As illustrated in FIG. 1, the related art processing system includes an antenna and RF processing unit 1 that communicates with a conversion unit 2, which performs analog-to-digital as well as digital-to-analog conversion for transmission and/or reception. A gateway 3 is connected between the conversion unit 2 and a terrestrial network 10.
In the gateway 3, uplinking is performed by a transmission baseband processing unit 6 that receives an input from the terrestrial network 10, and outputs a signal to a modulator 5, which outputs a modulated signal to a transmission intermediate frequency (IF) processing unit 4. The conversion unit 2 then receives the output of the transmission IF processing unit 4.
To perform downlinking, the gateway 3 includes a reception IF processing unit 7 that receives a signal from the conversion unit 2. A demodulator 8 demodulates the output of the reception IF processing unit 7 to a reception baseband processing unit 9, which is connected to the terrestrial network 10.
FIG. 2 illustrates additional details of the related art processing system. A RF antenna 11 receives the RF signal, which is down-converted to an IF in a heterodyne receiver 12. The heterodyne receiver 12 is connected to a synthesizer 13. At the IF stage, the individual subscriber channels are isolated and filtered in accordance with a control 14 and a filter 15. The isolated, filtered signals are then sent through a processing unit 16 to a demodulator 8, which includes an analog-to-digital converter 17. Channel processing units 18a . . . 18n in the gateway 3 receive and process inputs for the channels.
On the receive side, after demodulation, the bit stream is sent to the reception baseband processing unit 9 for further processing before going into the terrestrial network. The reverse operation takes place on the transmit side, as the transmitted signals are filtered, combined and up-converted to the RF frequency for transmission by the antenna 11.
Two related art methods are provided for the channel units 18a . . . 18n to perform signal processing on the related art systems illustrated in FIGS. 1 and 2. In the first related art method, the channel units are developed for the worst case channel conditions, so that receiver performance meets specifications. In the second related art method, the channel units are developed for nominal conditions. The first related art method has a higher cost than the second related art method, as the overall implementation cost of the gateway will be higher if all channel units are developed for worst case channel conditions. Further, the second related art method fails to meet basic performance requirements during the worst case channel conditions.
However, the related art processing systems have various problems and disadvantages. For example, but not by way of limitation, the related art system does not have channel units that have sufficient flexibility to adapt to channel conditions and/or propagation, and use different processing schemes based on channel conditions. Therefore, the related art systems are inflexible in terms of performance, even though implementation and control resides in the software. To guarantee a minimum level of performance, related art systems design the channel units for worst case scenario, which results in an increased cost. If the channels are of sufficient quality, the channel units are either underutilized or perform extra processing.